Chronic occlusion of blood vessels caused by atherosclerotic plaque affects millions of patients worldwide. Percutaneous Transluminal Angioplasty (PTA) is the endovascular treatment of election for treating atherosclerotic plaque causing reduction of the vessel lumen patency, thus hindering physiological blood flow. PTA is performed by means of inflating a balloon that has been transluminally advanced into the lesion site by means of catheters. The inflated angioplasty balloon applies a radial pressure to the inner wall of the vessel in the area of the atherosclerotic lesion. This results in redistribution of the plaque to a more favorable configuration (i.e., one in which the stenosed region of the vessel lumen is widened thus allowing blood flow to be restored). PTA alone may, in some cases, bring about the desired stenosis reduction and restoration of physiological blood flow through the treated vessel.
However, in many cases, PTA performed using just a standard dilation balloon is not sufficient for achieving long-term patency of the diseased blood vessel. Sometimes the standard dilation balloon is unable to redistribute the plaque in the desired manner due to consistency of the plaque or other factors. Also, even in cases where the balloon dilation may initially bring about the desired redistribution of the plaque, subsequent restenosis or reocclusion can occur. To deal with this, balloon dilation is often accompanied by stenting of the lesion using bare metal or drug coated stents. One or more stents, when properly positioned, can provide physical scaffolding to hold the redistributed plaque in place and/or to otherwise deter subsequent narrowing of the vessel lumen. Drug coated stents additionally elute drugs which deter local inflammatory or other physiological processes which may contribute to restenosis or reocclusion.
Another clinical option emerged in the last years is represented by the use of drug-coated balloons (Drug-Eluting Balloons, DEB) according to which the outer surface of the angioplasty balloon is coated with drugs characterized by antiproliferative properties, inhibiting restenosis of the vessel. Stenting and DEB themselves, though, are not perfect. Reocclusion still happens at a much too high rate. Both stenting and drug-eluting balloon treatment generally need an adequate pre-treatment of the vessel lumen. The preliminary plaque dilatation provided by balloon angioplasty has to be properly managed, in order to best prepare the lesion for the following treatment (DEB and/or stenting). An adequate preliminary erosion of the plaque can reduce the risk of restenosis after stenting or DEB treatment. Therefore, lesion pre-treatment by means of balloon angioplasty can be the key for long-term clinical success.
Also, in some cases, PTA using a standard balloon can cause unintended dissections, perforations or other types of damage to the blood vessel wall. This damage sometimes occurs due to poor elasticity of the diseased blood vessel wall. Such damage to the vessel wall can also result from mispositioning of the balloon during the procedure. Such mispositioning of the balloon may occur when a standard balloon is inflated within an atherosclerotic lesion that is fibrotic or of an angular shape, resulting in slippage of the balloon from the intended site of dilation.
Also, in some cases, PTA using a standard balloon can sometimes create non-uniform or uncontrolled tears in tissues of the vessel wall and/or vasospasm of the vessel wall.
At least some of the above-summarized problems may be overcome by the use of a cutting or scoring balloon as opposed to a standard angioplasty balloon. Generally, the presence of a cutting or scoring element on the outer surface of the balloon during the dilation causes specific, controlled scoring or cutting of the atherosclerotic plaque in combination with the balloon dilation. This may help to cause the plaque to be permanently redistributed in the desired manner and may avoid other problems such as balloon slippage, vessel dissection or perforation, non-uniform or uncontrolled tears and/or the occurrence of vasospasm due to excessive stretching or over-dilation of the vessel wall.
Cutting and scoring balloons of the prior art have had cutting blades (known as atherotomes) or scoring member(s) formed or affixed on the outer surface of the balloon. Thus, if a standard balloon is initially advanced to the intended site of a PTA intervention and the operator then makes a decision to use a cutting or scoring balloon for some or all of the procedure, it is then necessary for the operator to remove the PTA catheter having the standard balloon and replace it with another PTA catheter that has a cutting or scoring balloon. On the other hand, if the operator initially advances a cutting or scoring balloon to the site of the lesion but subsequently decides that a standard balloon would be a better option, the operator must then remove the PTA catheter having the cutting or scoring balloon and replace it with another PTA catheter that has a standard balloon.